Modeling and managing the variability of Web service-based systems

Web service-based systems are built orchestrating loosely coupled, standardized, and internetworked programs. If on the one hand, Web services address the interoperability issues of modern information systems, on the other hand, they enable the development of software systems on the basis of reuse, greatly limiting the necessity for reimplementation. Techniques and methodologies to gain the maximum from this emerging computing paradigm are in great need. In particular, a way to explicitly model and manage variability would greatly facilitate the creation and customization of Web service-based systems. By variability we mean the ability of a software system to be extended, changed, customized or configured for use in a specific context.We present a framework and related tool suite for modeling and managing the variability of Web service-based systems for design and run-time, respectively. It is an extension of the COVAMOF framework for the variability management of software product families, which was developed at the University of Groningen. Among the novelties and advantages of the approach are the full modeling of variability via UML diagrams, the run-time support, and the low involvement of the user. All of which leads to a great deal of automation in the management of all kinds of variability.     

B2B collaboration through web services-based multi-agent system

Web services open a door for better B2B collaboration in large distributed environment such as Internet. Process-oriented systems like workflow management systems have been taking the main role for web service-based B2B collaboration in such an environment. However, conventional workflow management systems don’t offer complete solutions for B2B collaborations considering many unsolved issues such as security, trust and complex and flexible interaction handling. In this paper, we propose a web service-based multi-agent platform, which can be used as a complementary solution for B2B collaborations. It fits naturally into the B2B interaction model and provides a very loosely coupled open system architecture.     

基于工作流模式的OWL-S过程模型分析及其应用

确定OWL-S过程模型描述Web服务之间交互协议的能力和缺陷，为组合Web服务执行提供有效支持。将组合web服务视为基于Web服务的工作流，利用OWL-S过程模型的控制结构给出工作流模式的实现方案，分析出OWL-S描述web服务之间交互协议的能力及缺陷；在此基础上，设计并实现基于OWL-S的组合web服务执行工具，通过验证Web服务调用的有效性及Web服务之间交互协议的有效性，提高组合Web服务执行的健壮性。     

Web service adaptation: A decade’s overview

With the exponential growth of communication and information technologies, adaptation has gained a significant attention as it becomes a key feature of service-based systems, allowing them to operate and evolve in highly dynamic and uncertain environments. Although several Web service standards and frameworks have been proposed and extended, existing solutions do not provide a suitable architecture, in which all aspects of monitoring and adaptation (e.g., proactive, cross-layer, and autonomic adaptation) can be expressed. In addition, the emergence of new computing environments to host and execute various types of services (Web/cloud services, big data-intensive services, mobile services, microservices, etc.) raises the need for more efficient monitoring and adaptation systems. This survey aims to bring a synthesis and a road-map to the adaptation of service-based systems. We also discuss adaptation solutions in emerging service models, such as cloud services and big services. Based on an adaptation taxonomy which we extracted from the surveyed approaches, and by identifying the main requirements and goals of service adaptation in Web, cloud and big data environments, detailed analysis and discussions, as well as the open issues, are provided.     

VxBPEL: Supporting variability for Web services in BPEL

Web services provide a way to facilitate the business integration over the Internet. Flexibility is an important and desirable property of Web service-based systems due to dynamic business environments. The flexibility can be provided or addressed by incorporating variability into a system. In this study, we investigate how variability can be incorporated into service-based systems. We propose a language, VxBPEL, which is an adaptation of an existing language, BPEL, and able to capture variability in these systems. We develop a prototype to interpret this language. Finally, we illustrate our method by using it to handle variability of an example.     

基于Web的情报信息系统的设计与实现

由于传统的公安工作缺乏技术平台支撑,在领导层决策分析时,需要进行大量手工统计,不仅工作量大而且分析过程缓慢,无法准确及时地指导工作,因此文中设计并实现了适用于公安部门的情报信息系统。以Internet中的Web服务器和Web浏览器设计为基础,介绍所开发的基于Web的情报信息系统,对其总体框架结构、主要功能等内容进行探讨和研究,构建了相应的设计资源库,并分析了实现该系统的一些关键技术。该系统的研发成功,使得公安部门能有效地实现数据资源的合理配置和利用,为公安部门提供了一个先进、实用、高效、成熟可靠的工作系统。     

Requirements capture and comparative analysis of open source versus proprietary service oriented architecture

Service Oriented Architecture (SOA) integrates information systems towards an agile and reusable service-based connectivity. It is an approach amalgamating large scale private/public computer systems and other resources with continuous phenomenal advent evolution and leveraging of the World Wide Web (WWW, commonly referred to as the Web) social media, mobile communications, Big Data (BD), data analytics, Machine Learning (ML) based optimisation, Cloud Computing (CC) and Internet of Things (IoT), commonly known as Advanced Technologies (AT). Implementing SOA, whether Open Source Software (OSS) or proprietary or absolute freeware is a choice to be made which depends on the organisation's requirements in light of AT as well as a host of delivery and security concerns. In this paper, a comparative analysis of an open source vs. proprietary SOA for large scale computer systems servicing AT is presented by examining their main efficacies, features, advantages and disadvantages and capturing their generic technical functional and non-functional requirements in a unified manner. Furthermore, the SOA evaluation criteria, recommendations and conclusions are also presented.     

Dynamic replication and synchronization of web services for high availability in mobile ad-hoc networks

Web services are gaining high popularity and importance on mobile devices. Connected to ad-hoc networks, they provide the possibility to establish spontaneously even complex service-based workflows and architectures. However, usually these architectures are only as stable and reliable as the underlying network infrastructure. Since topologies of mobile ad-hoc networks behave unpredictably, dependability within them can be only achieved with a dynamic replication mechanism. In this paper we present a highly flexible solution for replication and synchronization of stateful Web services and discuss the behavior of the implemented prototype in large-scale simulations.     

基于RBAC的权限管理在Web中的设计与实现

访问控制技术在Web信息系统中已得到了大量应用。相对于传统的自主访问控制模型和强制访问控制模型,基于角色的访问控制（RBAC）具有降低授权管理复杂性、减少管理开销以及能提供与企业组织结构相一致的安全策略等优势。文章使用J2EE的框架Struts2设计并实现了基于RBAC的权限管理。     

基于服务交互行为的复杂服务协同网络建模

随着分布式计算技术的发展,以自治的服务协同与互操作为主要构造手段、结构与行为随需而变的面向服务的软件系统已成为当前主流的软件架构,分析并理解服务交互行为对于这类复杂软件系统的开发、维护和运营具有重要意义.针对面向服务的软件系统中基本构成元素Web服务的复杂交互执行行为,考虑到服务自治性及系统规模化所带来的复杂性,借鉴复杂网络建模分析方法,提出了一种考虑服务行为特征的服务动态行为生长演化模型.模型首先以真实服务的服务结构数据为基础,以服务间参数关联关系为核心,通过参数匹配建立服务结构网络作为基本连通性约束,代表可能发生交互关系的服务.然后,基于服务间的择优选择、组合交互及动态重组等特性,对面向服务的软件系统生长演化及动态执行行为进行了仿真建模.在Seekda及QWS数据集上进行了仿真实验,结果表明:与传统的软件系统的层次性结构有所不同,由自治的Web服务所构成的软件系统具有更强的模块性;与系统中个体服务演化规则,如择优连接及动态重组相比,服务结构网络的性质对系统最终形态有更重要的影响,相关结果对大规模服务软件的构建及分析具有重要的指导意义.     

一个基于Web服务的在线优化和监控系统

在流程工业,许多信息集成系统通过CORBA／Agent技术来实现,这些集成方案在实时性,安全性,以及数据通信的稳定性等方面尚待改进。为了研究更加合理的集成方案,实现了一个基于Web服务的在线优化和监控系统,在这个系统中,专业软件Matlab,G2,GAMS被分别封装成Web服务并在UDDI注册中心注册,然后实现了这些Web服务的集成。最后,通过在尼泊丁乙酯合成过程中的应用．证明了该在线优化和监控平台的有效性和适用性。     

Service-based computing on manets: enabling dynamic interoperability of first responders

Mobile ad hoc networks will form a critical part of the first-responder communications infrastructure. Empirical data shows how network-aware, autonomous, mobile agents can manage information services on live manet environments. A multidisciplinary team in Drexel University's College of Engineering has been working with local law enforcement and transportation officials to identify problems in enabling police, fire, security, and other public protectors to effectively communicate and collaborate in first-response situations. Development of the Philadelphia Area Urban Wireless Network Testbed (PA-UWNT) is part of this effort. The PA-UWNT is a mobile ad hoc network (manet) comprising mobile computers (PDAs, tablets, and laptops) and Web service-based applications. Our experience in the PA-UWNT project indicates that constructing such systems will require new research developments in computer networking, agent and service-based computing, and security that integrate each of these disciplines at several fundamental levels. In this paper, we outline part of this approach through experiments demonstrating the utility of integrating the network and agent layers and enabling agents to reason about the current operating context. We posit that autonomous agents that can reason about the network's slate and services offer an effective means of meeting the manet environment's challenges.     

Web服务安全模型研究与实现

随着Web服务在分布式系统中的广泛应用,安全问题日益突出。论文基于WS-Security和WS-Policy协议,提出一个Web服务安全模型,并在.NET环境下,使用WSE2.0Web服务开发组件实现了该模型。该安全模型灵活、可扩展,既保证了SOAP消息端到端的安全性,又通过安全策略文件提高了Web服务的互操作性,可满足Web服务应用环境下的安全需求。     

安全的Web服务集成框架分析与设计

提出了一个可扩展的Web服务的安全体系架构模型：SX_RSRPM模型,该模型通过对协议栈进行安全性扩展和增加安全认证角色有效地提高了Web服务的安全度。在基于XML的安全技术、WS_Seclurity协议的分析基础上,提出了Web服务的应用安全层次结构,并在开发OPEN-CLASS平台的过程中形成了一个实用的Web服务应用安全集成方案。     

Security Maintenance Mediation: a technology for preventing unintended security breaches

Web‐resident information is becoming ‘smarter’, in the sense that emerging technology will support the annotation of it with ontological terms, which will be used to locate and reuse information. This will pose a great security risk in the form of unintended breaches (as distinct from deliberate invasions). Web‐resident information will be far more readily available and relevant, thus causing inadvertent releases of secure information to potentially cause it to be diffusely spread across the Internet. Then as this information is iteratively transformed and integrated with other information, it will become irretrievable and potentially used in a myriad of unpredictable ways. The problem is that ontological annotations, while making information more understandable in its original form, do not provide a means for easily capturing the complex semantics of information that has been transformed via abstraction, aggregation, and integration. This demands the development of a semantically rich way of specifying ‘views’ of Web information, to which security controls can be attached. Also needed is a way for users of secure information to easily and voluntarily blend—and thereby propagate—security controls as information is transformed. Information mediators designed by collaborative teams of experts are proposed as the vehicle for wrapping information, so that at each step of reuse, high‐level views and their corresponding integrity controls can be made easily accessible to trusted users who will then be able to ensure their proper maintenance. Copyright © 2004 John Wiley & Sons, Ltd.     

基于LNMPA架构的Web系统设计与实现

伴随数字化、网络化的快速发展,高校内涌现出众多的Web系统,这些Web系统参差不齐,安全性、易用性、可靠性等无法得到保障。把LAMP架构与LNMP架构各自的优点结合在一起形成新的网站服务器架构LNMPA,分析了该架构的特点及优势。采用基于MVC设计模式的ThinkPHP框架设计并实现了一套通用Web系统,该系统具备成本低、扩展灵活、性能稳定、数据安全、抗并发能力强等显著特点。     

基于服务的网络体系结构的设计和实现

对网络体系结构的研究现状进行了介绍.基于MCES(micro-communicationel ement structure)架构设计了一种基于服务的网络体系结构原型.在原型系统中,实现了服务元的合理组合和调度,并从体系结构上更好地支持QoS和网络安全.同时,通过改进的套接字机制实现了向后兼容现有TCP/IP网络应用程序,满足了用户不断增长的网络服务要求.基于Linux的实验结果显示,该体系结构组成的系统是合理的、可行的,并具有很好的传输效率和可扩展性.     

Specifying and enforcing application-level Web security policies

Application-level Web security refers to vulnerabilities inherent in the code of a Web-application itself (irrespective of the technologies in which it is implemented or the security of the Web-server/back-end database on which it is built). In the last few months, application-level vulnerabilities have been exploited with serious consequences: Hackers have tricked e-commerce sites into shipping goods for no charge, usernames and passwords have been harvested, and confidential information (such as addresses and credit-card numbers) has been leaked. We investigate new tools and techniques which address the problem of application-level Web security. We 1) describe a scalable structuring mechanism facilitating the abstraction of security policies from large Web-applications developed in heterogeneous multiplatform environments; 2) present a set of tools which assist programmers in developing secure applications which are resilient to a wide range of common attacks; and 3) report results and experience arising from our implementation of these techniques.     

基于网络的Context Aware智能控制系统

提出一种基于网络的Context Aware智能控制系统的体系结构、Context任务控制管理模型。系统将机器人作为Context Aware智能系统的智能接口。通过对Java JINI的服务查找机制进行修改,增强了JINI的服务查找、分发机制,使得系统可以通过综合分析服务提供者当前状态、服务申请者的状态、系统当前的性能以及Context感知信息,经模糊决策,通过”Pull”方式,或“Push”方式给服务申请者(或第三方用户)提供所需的服务。最后对系统性能进行分析。一个应用实例说明Context Aware智能控制系统的应用。     

一种支持可信Web服务的应用框架

Web服务技术给开发基于Web的应用带来了新的机遇和效益，但系统安全性却不利于其应用性。本文通过扩展Web服务安全规范实现了一种支持可信服务的机制．提出了电子商务和电子政务中Web服务安全性的实际解决方案。